A hybrid electric vehicle (HEV) utilizes an electric motor/generator unit (MGU) that includes an alternating current (AC) electric motor in conjunction with an internal combustion engine (ICE), and an electronic control unit (ECU) that controls use of the MGU and the ICE to improve efficiency. In some HEVs, the ICE drives a generator which in turn powers the electric MGU to power the vehicle. In other HEVs, both the electric MGU and the ICE can provide power to drive the vehicle's transmission depending on the mode of operation.
In addition to the MGU, most HEVs include an inverter-controller unit that includes an inverter module controlled by a control unit. The inverter module includes a number of inverter sub-modules. The AC electric motor includes a number of motor windings which can be coupled to the inverter sub-modules. The inverter sub-modules can be rapidly switched by a control unit to convert the DC power provided by a battery to AC power. The inverter module provides this AC power to the AC electric motor to sequentially energize the motor windings at appropriate times to produce a rotating magnetic field that causes rotation of the AC electric motor's permanent magnetic rotor and drives the AC electric motor. In addition to supplying power to the MGU when it acts as a motor, the battery can receive power from the MGU when it acts as a generator, which allows the HEV to recharge the battery with power recovered from braking or with power from the ICE.
In addition to the propulsion battery, which is often high-voltage, that is more than 60 volts, many HEVs also employ a low-voltage auxiliary battery (i.e., a 12-volt car battery) to power various vehicle electrical loads. The low-voltage auxiliary battery can be recharged by an auxiliary power module (APM) that manages charge across the low-voltage auxiliary battery. The APM can function as a DC-to-DC converter that converts electric power at the higher voltage of the propulsion battery to electric power at the low voltage of the low-voltage auxiliary battery and vehicle electrical loads.
Accordingly, it is desirable to provide an HEV power system that is less expensive to manufacture and maintain. For instance, it would be desirable to eliminate the need for separate high-voltage and low-voltage batteries and/or the need to expensive components such as the APM. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.